[PATCH v2 1/4] PCI: rockchip: limit RK3399 to 2.5 GT/s to prevent damage

[Geraldo Nascimento]

On Wed, Dec 24, 2025 at 2:18 AM Anand Moon <linux.amoon at gmail.com> wrote:
>
> Hi Geraldo,
>
> On Tue, 18 Nov 2025 at 03:17, Geraldo Nascimento
> <geraldogabriel at gmail.com> wrote:
> >
> > Shawn Lin from Rockchip has reiterated that there may be danger in using
> > their PCIe with 5.0 GT/s speeds. Warn the user if they make a DT change
> > from the default and drive at 2.5 GT/s only, even if the DT
> > max-link-speed property is invalid or inexistent.
> >
> > This change is corroborated by RK3399 official datasheet [1], which
> > says maximum link speed for this platform is 2.5 GT/s.
> >
> > [1] https://opensource.rock-chips.com/images/d/d7/Rockchip_RK3399_Datasheet_V2.1-20200323.pdf
> >
> To accurately determine the operating speed, we can leverage the
> PCIE_CLIENT_BASIC_STATUS0/1 fields.
> This provides a dynamic mechanism to resolve the issue.
>
> [1] https://github.com/torvalds/linux/blob/master/drivers/pci/controller/pcie-rockchip-ep.c#L533-L595
>
> Thanks
> -Anand

Hi Anand,

not to put you down but I think your approach adds unnecessary complexity.

All I care really is that the Kernel Project isn't blamed in the
future if someone happens to lose their data.

Thanks,
Geraldo Nascimento